Rootstalk creeping, not cordlike, internodes very short, less than
&frac14", heavily beset with old petiole bases; hairs absent; scales brown.

Sori few and scattered, back from leaf edge.

Indusia cup-shaped, typically with hairs.

Spores spiny.

Identification:

Identifiable as a Bladder Fern by thrice-cut, lacy fronds which are widest
at the base.

WARNING: Cystopteris species are distinguished from one another
with great difficulty and often not a little bit of frustration. The "distinguishing"
characteristics are often difficult to identify clearly and there is a fair
amount of overlap. That said:

Distinguished from St. Lawrence Bladder Fern, Cystopteris
laurentiana by frond axis and leaflet ribs densely
covered with hairs, by frequently bearing bulblets, and byall
but the earliest fronds of the season bearing sori. The frond axis and
leaflet ribs of St. Lawrence Bladder Fern is only sparsely
covered with hairs, occasionally bearing bulblets (often misshapen),
and nearly all leaves bear sori.

Field Marks

rocky habitat, especially rock faces

triangular fronds with stretched tips

tiny hairs on frond axis and leaflet ribs

bulblets on leaflet edges

Distribution:

Ontario to Newfoundland, south to Missouri, Arkansas, Texas, Alabama,
and Georgia. Also Utah, Arizona, and New Mexico.

Habitat:

Cracks and ledges on moist, shaded cliffs and outcrops; usually on calcareous
substrates

On rock in dense woods; occasionally on the ground in northern swamps.